Device for selectively discharging refuse material for separate recovery of fibrous material

ABSTRACT

A device for discharging inhomogeneous material such as household garbage from a vacuum conveying system, said device comprising means permitting a lighter fraction of said material substantially comprising fibrous material to be discharged separate from the rest of the material.

United States Patent 1191 Naumburg et al.

[11] 3,826,366 1451 July 30, 1974 DEVICE FOR SELECTIVELY DISCHARGING REFUSE MATERIAL FOR SEPARATE RECOVERY OF FIBROUS MATERIAL Inventors: Per Anton Naumburg, Djursholm;

Hans Olof Hydn, Stockholm, both of Sweden Assignee: AB Centralsug, Solna, Sweden Filed: Feb. 13, 1973 Appl. No.: 332,100

Foreign Application Priority Data Feb. 25. 1972 Sweden 2385/72 US. Cl 209/74, 209/115, 209/135 Int. Cl. B07c 3/06 Field of Search 209/115, 74, 121, 134,

Primary ExaminerM. Henson Wood, Jr. Assistant Examiner-Gene A. Church Attorney, Agent, or Firm-Spencer & Kaye [57 ABSTRACT A .device for discharging inhomogeneous material such as household garbage from a vacuum conveying system, said device comprising means permitting a lighter fraction of said material substantially comprising fibrous material to be discharged separate from the rest of the material.

8 Claims, 2 Drawing Figures DEVICE FOR SELECTIVELY DISCHARGING REFUSE MATERIAL FOR SEPARATE RECOVERY OF FIBROUS MATERIAL Garbage and similar mixed material, such as certain types of industrial refuse, comprise as a rule a comparatively high percentage of fibrous material the recovery of which for renewed use is an important task in respect to the menacing fibre shortage in the world. The fibrous material in garbage is in part in the form-of loose paper, in part in the form of paper-wrapped packets, in part as paper bundles such as newspaper bundles, catalogs or the like having comparatively high density. Whereas loose paper and wrapping paper as a rule is released during the transport of the garbage from the rest of the garbage having higher specific weight, paper bundles, catalogs, board, in particular cardboard boxes normally follow with the heavy components of the garbage rather than to be separated therefrom. This is particularly the case when the garbage is conveyed by suction in closed conduits. However, the fibrous material in garbage to the greatest part comprises loose paper or wrapping paper released from its contents, such paper during suction-transport being inclined to follow with the air stream at higher velocity and substantially separate from the heavier material components.

The invention starts from the basic'idea that it may be advantageous under the fibre recovery aspect to recover from garbage and similar mixed material only that part of its content of fibrous material which is airborne in the conveying air stream, no attempt being made to recover agglomerated fibre material forming part of the slower stream of heavier material. For this purpose the invention contemplates a'device for recovering fibrous material from mixed material such as garbage, which in and by an air stream is conveyed through a collecting conduit from a collecting system to a terminal station where specifically heavier and lighter fractions of the material are.selectively separated from the air stream and are discharged therefrom to separate places outside the air stream, such discharge being performed with the state of vacuum in the conveying system being substantially maintained.

Fibre recovery is further improved by the provision of means enabling the percentage of loose paper in the collected and conveyed material to be increased at the expense of the proportion of heavy compact fibrous material discharged together with the heavy material. A measure which is particularly advantageous in this connection consists in providing, at positions where fibrous refuse is produced in particularly great amounts and possibly in packed, tied or bound condition, specific fibre material introduction openings combined with means for subdividing the agglomerated fibrous material into pieces which are more inclined to follow with the air stream than to behave as heavy fraction material.

Unavoidably, of course, a part of the loose fibre material will be entangled in the heavy'material fraction but it may be assumed that already a very simple arrangement according to the present invention enables about 80 percent of the total fibrous material forming part of e.g. normal household garbage to be separately discharged. The remaining fibrous material following with the heavy material will in such a case not motivate any additional separation measures.

The invention is explained moreclosely by reference to the attached drawings in which 7 FIG. 1 is a schematic representation of a terminal station of a pneumatic garbage conveying system with material discharge performed in two steps, and

FIG. 2 is a schematic representation of a terminal station having a material classifying screw provided between the heavy material outlet and the light material outlet.

in the system schematically shown in FIG. 1 mixed material, for example garbage from a conventional collecting system (not shown) comprising introduction chutes and connecting conduits is supplied to a collecting conduit 1 which via a separating arrangement comprising first and second separators 2 and 3 is connected to'an air outlet 4 leading via a fines separator or filter 5 to the suction side of a suction machine unit 6 from which the air from which the conveyed material has been removed in separators 2 and 3 and which has been cleaned in the filter 5 is discharged to the atmosphere.

In similar, previously known systems the separation of all the material conveyed in the air stream has been performed in a unitary separator, frequently of cyclone type, the material outlet of which was connected to a device for discharging the conveyed material with the subatmospheric pressure maintained in the conduit system. In this case there unavoidably occurred a mixture between the various material fractions so that the material discharged from the system comprised both heavy material such as metal and glass articles, and light material such as paper and plastic. According to the invention there is obtained a subdivision of the material into two fractions of which the secondarily collected fraction to the overwhelming part, i.e. apart from a certain content of plastic material, consists of fibrous material suitable for renewed use. For this purpose, a conduit 10 is branched-off from the substantially straight collecting conduit 1 to feed said first separator, the heavier fraction material conveyed by the air stream along the bottom of the collecting conduit 1 entering into said conduit 10 under the action of gravity whereas the airborne light material fraction follows with the main stream of the conveying air through the extension of collecting conduit 1 beyond the branching point. The heavy material from branch conduit 10 enters into a receiving chamber 11 having a bottom opening to which a compactor 12 is connected. A reciprocating piston or a conveyor screw forming the propelling element of the compactor feeds the heavy material received in the direction of and through an outlet port into a conveying container which is attached to the outlet port of the compactor in an air-tight manner and which after filling is exchanged against an empty container.

When the heavy material enters into chamber 11 a further part of the light-weight material is released which together with the partial air stream passing through conduit 10 and separator 2 is again introduced into the collecting conduit 1 via a return conduit 14. The collecting conduit 1 terminates in the lighter fraction material separator 3 which here is schematically illustrated as a cyclone having a central air outlet 4 at the upper end and an air-tight material discharge sluice 20 at the lower end.

It is worth noting that an important advantage of the invention resides in that after the preceding separation of the heavymaterial in the first separator 2 the cyclone used for the separation of the light-weight material may be constructed in respect to reduced strain requirements and that its construction can be particularly adapted to the specific character of the residual light material fraction. The reduction in cost obtained thereby and the increase in the effectiveness of separation will to a certain extent balance the increase in cost caused by the incorporation of the heavy material separator 2 into the system.

Finally, it may be maintained that the discharge of the light-weight material through sluice 20 does not require an equally complicated and bulky arrangement as required for vacuum-tight discharge of the heavy material. As the light-weight material substantially consists of highly conpressible fibrous material the arrangement may be such that with the aid of a piston or screw :1 successively discharged plug of material is formed in the outlet, said plug during discharge effectively preventing air from penetrating into the suction system.

If for some reason it appears desirable to reduce the spacing between the heavy material and light material separators an arrangement of the type shown in FIG. 2 may be used in which the collecting conduit 1 opens into a chute 30 to the bottom of which, not shown, a heavy material outlet, for example of the type described in connection with FIG. 1, is attached. Said chute 30 and outlet together form a first or heavier fraction separator.

The conveying air is discharged through a passage 31 formed by a drum slowly rotating about an essentially horizontal axis and having an inwardly extending helical guide wall 32, the halves of which counted from a transverse central section plane are threaded in opposite directions in such a way that heavier material accide'ntally introduced by theair stream into the drum 31 and supported by the cylindrical wall thereof is repulsed and returned back into chute 30 whereas lightweight material foliowing with the air stream will pass without hinder through the drum passage past the helical wall 32 and into a chute 33 which atthe lower end opens into a light material outlet not shown Said chute 33 and outlet together form asecond or lighter fraction separator.

The air is discharged through an outlet 34 leading to an air cleaning and suction machinery, for example, corresponding to parts 4, and 6 in FIG. 1. The outlet 34 is in communication with the passage through drum 31 and chute 33 via a material rejecting drum 35 rotating concentrically with the outlet 34 and having at the v end facing the outlet 34 an opening communicating with the outlet whereas the opposite end surface is closed. About its periphery the drum 35 is provided withlongitudinal apertures between a system of longitudinally extending ribs so that air can enter into the interior of the drum and be discharged through the one end surface of the drum into outlet 34 whereas lightweight material conveyed by the air will be flung away centrifugally under the action of the ribs from the drum surface and out of the path of the air stream to permit such light-weight material to fall down towards'the bottom of chute 33 to be dischaged therefrom. Whereas drum 35 is driven at the high speed required for the described centrifugal action by a motor not shown, a motor 40 driving drum 31 at a considerably lower speed is provided on the housing of the separator unit. Motor 40 engages a gearing 41 which in turn is in driv- 4 ing engagement with a rack 42 extending about the periphery of drum 31.

. The advantages obtained by the embodiment shown in FIG. 2 reside, on the one hand, in that a sharper separation of the material into a heavy-weight and a lightweight fraction is obtained by means of the helical wall of drum 31 and, on the other hand, that the separation of the light-weight material from the air stream can take place without the use of a cyclone, i.e. with reduced space requirements. Theair flows in a straight, comparatively short path from the upper end of separation chute 30 to the outlet 34. g

The discharge of the material fractions from chutes 30 and 33 respectively may of course be performed as described above or in any other suitable way.

As far as discharge of light material from the second separator in the form of a self-sealing plug is concerned, outlet constructions suitable for this purpose are disclosed and shown in the commonly assigned application entitled Discharge Device, invented by Hans Olof Hydn filed on the same day as this application and corresponding to Swedish application No. 2384/1972 filed in Sweden on Feb..25, 1972.

What we claim is:

1. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprisinga collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying sys .tem, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said first separator comprising a chamber connected to said branched-off conduit, a return conduit connecting said chamber with said collecting conduit downstreams said branched-off conduit, a material collecting room underlying said chamber and in open communication therewith, and means operable to discharge material from said material collecting room to a place outside said conveying system with the state of vacuum maintained in the conveying system.

2. The device as claimed in claim 1 in which said discharge means comprise an outlet port in said material collecting room, an exchangeable receiving container sealingly attached to said outlet port, and a propelling member operating in said material collecting room to move said heavier fraction material towards and through port outlet prot and into said receiving container to be compacted therein.

3. The device as claimed in claim 1 in which said second separator is of the cyclone type.

4. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected, to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying sys tem, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, a section of said collecting conduit between said branched-off conduit and said second separator comprising a cylindrical drum rotatable about a substantially horizontal axis and having an open entrance end near said branched-off conduit and an open exit end near said second separator, an inwardly projecting guide wall of helical configuration extending from said entrance end over at least part of the length of said drum, and means for rotating said drum about'said axis in a direction to cause said guide wall to return by screwing action heavier fraction material accidentally introduced into said drum and supported by the cylindrical wall thereof back into said branched-off conduit.

5. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device'comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream,.said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said collecting conduit being upstream of said device and in communication with specific fibre material inputs in addition to inputs for said refuse material containing heavier and lighter fractions.

6. The device as claimed in claim 5 in which at least some of said specific fibre material inputs are provided rial, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne light fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said second separator comprising a discharge port leading to the outside atmosphere and means adapted to compact separated lighter-fraction refuse material to form a plug successively discharged from said discharge port and forming a seal therein againstpenetration of air into the vacuum conveying system.

8. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said devicev comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said second separator having an inlet connection tosaid collecting conduit, an air outlet leading to a vacuum pump unit, and laterally of an air flow path formed between said inlet connection and said air outlet, a sluice-like material outlet, a drum being rotatably supported in a position intercepting said air flow path, said drum having one closed end wall and a port in the other end wall leading from the interior of said drum into said air outlet, the periphery of said drum being bounded by spacedapart axially extending rod-like elements, and means rotating said drum at a speed sufficient to cause said rod-like elements to intercept any air-borne material and centrifugally to fling such material out of said air flow path. 

1. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said first separator comprising a chamber connected to said branchedoff conduit, a return conduit connecting said chamber with said collecting conduit downstreams said branched-off conduit, a material collecting room underlying said chamber and in open communication therewith, and means operable to discharge material from said material collecting room to a place outside said conveying system with the state of vacuum maintained in the conveying system.
 2. The device as claimed in claim 1 in which said discharge means comprise an outlet port in said material collecting room, an exchangeable receiving container sealingly attached to said outlet port, and a propelling member operating in said material collecting room to move said heavier fraction material towards and through port outlet prot and into said receiving container to be compacted therein.
 3. The device as claimed in claim 1 in which said second separator is of the cyclone type.
 4. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, a section of said collecting conduit between said branched-off conduit and said second separator comprising a cylindrical drum rotatable about a substantially horizontal axis and having an open entrance end near said branched-off conduit and an open exit end near said second separator, an inwardly projecting guide wall of helical configuration extending from said entrance end over at least part of the length of said drum, and means for rotating said drum about said axis in a direction to cause said guide wall to return by screwing action heavier fraction material accidentally introduced into said drum and supported by the cylindrical wall thereof back into said branched-off conduit.
 5. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising a collecting conduIt through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said collecting conduit being upstream of said device and in communication with specific fibre material inputs in addition to inputs for said refuse material containing heavier and lighter fractions.
 6. The device as claimed in claim 5 in which at least some of said specific fibre material inputs are provided with means for subdividing coherent agglomerations of fibre material into air stream-borne pieces.
 7. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising fibrous material, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne light fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said second separator comprising a discharge port leading to the outside atmosphere and means adapted to compact separated lighter-fraction refuse material to form a plug successively discharged from said discharge port and forming a seal therein against penetration of air into the vacuum conveying system.
 8. A device for selectively discharging refuse material containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum conveying system comprising a collecting conduit through which said refuse material is conveyed in a suction-induced air stream, said device comprising a conduit branched-off from said collecting conduit in a position gravitationally to receive heavier fraction refuse material, a first separator connected to said branched-off conduit and permitting such heavier fraction material to be separated from the air stream with the state of vacuum maintained in the conveying system, and a second separator terminating said collecting conduit and passed by said air stream, said second separator permitting air stream-borne lighter fraction refuse material to be separated from said air stream with the state of vacuum maintained in the conveying system, said second separator having an inlet connection to said collecting conduit, an air outlet leading to a vacuum pump unit, and laterally of an air flow path formed between said inlet connection and said air outlet, a sluice-like material outlet, a drum being rotatably supported in a position intercepting said air flow path, said drum having one closed end wall and a port in the other end wall leading from the interior of said drum into said air outlet, the periphery of said drum being bounded by spaced-apart axially extending rod-like elements, and means rotating said drum at a speed sufficient to cause said rod-like elements to intercept any air-borne material and centrifugally to fling such material out of said air flow path. 